Method of treating mixtures of amines



Patented Nov. 18,

1 UNITED STATES PATENTTVOFFICVEI HAROLD s. ADAMsjor LARCI-IMONT, NEW YQRKQANI) LUDWIG MEIUSER, or BOUND BROOK, New JERSEY, ASSIGNORS To THE NAfiGATZUCK CHEMICAL COMPANY, or

N EW' HAVEN, CONNECTICUT, A CORPORATION- OF CONNECTICUT p v mn'rn'on or TREATING MIXTURES or AMINES i No Drawing.

Most processesfor the manufacture of alkyl amines yield a mixture of primary, secondary and tertiary amines, which mixture. must then be put through a separating process,

5 usually distillation to recover the several amines in a relatively uncontaminatedstate. The 'alkylation of aniline or its homologues in the] manufacture of mixed alkyl aryl amines usually gives a mixture .ofsecondary and tertiary amines which must be fur ther separated. Obviously thesedoub-le-stage processes have the effect of. increasingfithe cost of the individual'amines which are be 1; ing' manufactured. There are certain-chemical reactions in which the by-product, orbyproducts, may consist largelylor in part, as the case may -be of amines, and most frequently mixtures of primary, secondary and. tertiary amines.

amines themselves. [Another object oftheinvention is to utilize a mixture of primary,

secondary, and tertiaryamines for; the form'ation of useful products." Still another'obje'ct is to provide an improved method Q0 for manufacturing thluramdisulphides from mixtures of amines. TA further. ObjBCtxiS to. recover tertiary amines from mixtures with primary and secondary amines. The invention alsoincludesthe manufacture of'tetra alkvlated thiuramdisulphides.

lVith a preferred method in mind, but without desiring to place undue limitations upon the scope of theinvention beyond what 40 may be required by the prior art, the invention briefly consists intreating a mixture of primary, secondary and'tertiary amines with carbon bisulphide, oxidizing the reaction products, andremoving them, and recovering 4 5 tertiary amine from the solution." 1

Application filedAug ust 4, 1925. Serial No. 48,070.

Vi hen a mixture of amines dissolved in water or in another suitable solvent is treated with carbon bisulphide, the primary and secondary amine may function in two ways.

' One molecule of either may add to the car-' bon bisulphide to form the corresponding dithiocarbamic acid. Another molecule ofeither'primary or secondary amine may 'functi'onas a base,'reacting with the dithiocar bamic "acid which has been formed to yield the corresponding alkyl ammonium salt. The tertiary amine which maybe present in the mixture functionsonly as a base.

These reactions maybe expressed:

lAs 'a specific example, thefollowing given: A watersolution of'dimethylamine and trimethylamine sulphate, containing a trace of methyl aminesulphate, thefmixture of the amines," containing 19.3 lbs.

of nitrogen, may be treated with" 55.0-

lbs. of'sodium hydroxide dissolved in Water. This amount of sodium hydroxide is the exact amount required to liberate the amines from their salts. By maintaining thetemperature at 2O25 C. andkeeping the concentration of the reaction mixture below the saturation point of the amines in the water present, the amines can be retained in solu tion without any loss. To the solution of free amines may then be added 52.4: lbs. of carbon bisulphide. ,Then,with stirring and cooling, 156 lbs. of a 7.5% solution of hydrogen peroxide containing 34.6 lbs. of 98% sulphuric acid is slowly run in. Tetramethylthluramdisulphide is formed in this reaction by the oxidation of the dithiocarbamic acid compound of the secondary amine. The -tertiary amine remains insolution as the sulphate. The primary amine reaction product Will be oxidized at the same time to the'corresponding mustard oil. The latter reaction may be briefly expressed as When the primary amine is present only in very small amounts or in traces, the thiuranr.

disulphide canbe nicely precipitated and can be easily filtered out of the reaction mixture.

' The filtrate may then be concentrated, andany amine which has remained dissolved as sulphate may then be liberated by the further addition of 27 .5 lbs. of sodium hydroxide in water solution, again maintaining temperature and concentration conditions so that the amines will remain in solution. tion of 26.2 lbs. of carbon bisulphide followed by theaddition'of 78.2 lbs. of a 7.5% solution of hydrogen. peroxide containing 17.3 lbs. of

98 sulphuric acid, added with stirring and cooling, formsa further amount of the thiuramdisulphide which may be filtered, Washed and dried,.and combined with the disulphide formed above; 'The filtrate now contains only teritiary methyl amine sulphate and sodium sulphate in water. The tertiary amine may be recovered by makingthe solution alkaline, distilling ofi'the amine, and absorbing it in water. The object of the second treatment with carbon bisulphide is to recover any primary or secondary amine or both which may have functioned as abase in the first re action. If, howeventhe amount of tertiary amine presentis exactly suiiicient to neutralize the dithio carbamic .acid formed by the primary and secondary'amines in reaction 7 with thec arbon bisulphide, the result will be The addivthe carbon-disulphide The reactions may be expressed:

=S NRz R2NH+H202 (3% solution) CO; (RzNH)1HzS O4+HzO1 (3% solution) No reaction thus the reaction mixture may be maintained neutral throughout.

lit the amount of primary amine in the mixture is. large, the muStard oil formed after oxidation of the dithiocarbainic acid may cause the thiuramdisulphide to appear as a gummy mass. I This mustard oil may be separated from thethiuramdisulphide by steam distillation or other suitable means. If the amount of mustard oil'be small, the thiuraindisulphide willprecipitate normally, and the mustard oil can be volatilized away during the drying operation.

V Theseparation of the mustard oil from the thiuramdisulphide may be carried out with quantitative precision, thus indicating that the method in the above example can be read ily employed as a-quantitative means of analyzing a mixture of amines for the amount of primary, secondary and tertiary amine present.

The following example may be used to illustrate the invention: In the manufacture of triethyltrii'nethylenetriamine which consists in adding ethyl chloride to hexamethylenetetramine, hydrolizing the addition product, and condensing the amine so formed with the formaldehyde simultaneously liberated,

there results a by-product containing sub-- stantially ammonia, primary, secondary and v'almines liberated by the-sodium.hydroxide tertiary niethylamines, and primary ethylamine. Of the four nitrogens i'n'hexamethylenetetramine only one'appears as triethyltrimethylenetriamine, 'and of the six methyl-- ene "groups, only one. The by-product accordingly results from, the action of the methylene'residues on the ammonia whereby the latteris more or less methylated-toform methyl amines. The by-product contains secondary and tertiary methylamine together.

with traces of primary methyl amine and ethyl amine, vethyl methyl amine, diethyl amine, methyl methyl ethyl amine, and methyl ethyl ethyl amine. To a solution of 1 these amines as sulphates containing in total, 42.8 lbs. of nitrogen,'isfadded'122.4 lbs. of

sodiumhydroxide dissolved in water. The

may be evolved by heating and subsequently absorbed in water. This amine solution may then betreated with116.3 lbs. of carbon bisulphide, and then, .with cooling and stirring is further 'treatedwith 348 lbs. of a 7 5% solution of hydrogen peroxide 'containing 76.8 lbs. of 98%. sulphuricacid. As in the first example thedithiocarbamie acid reaction products 'areloxidi'zed to'tetra-a-lkylated thiu'ramdisulphide. The disulphide appears as a precipitate and maybe filtered out, washed 3 and dried. Thefiltrate from the tetra-alkylated thiuramdisulphide may then be concentrated' and neutralized by the addition of 61.2 lbs. of soduim hydroxide dissolved in water, adding the sodium hydroxide slowly to prevent thereaction mixture from becoming heated, and further mamtammg the temper' ature'and concentration at a point at which 7 the'amine will remain solution and will not be volatilized. To the'solution' of amines thus obtained are then added 58.2 lbs. of car-.

hon bisulphide andthereaften. with stirring and cooling, 17 lbs. of a solution'of. hydrogen peroxidedissolved in water,:con-

taining 38.3 lbs. of 98% sulphuric'acid. The tetra-alkylated thiuramdisulphide thus formed maybe filteredout, washed and dried. T he', filtratecontains'only tertiary amine sulphates'togethe'r with sodium sulphate. The amines may be recovered by making the solutionalkaline, boiling off the amine, andab f sorbing the water; p a

; As triethyltrimethylenetriamine does not react with sodium hydroxide nor with car-v bon disulphide, it is not essential to-sepam ratethe former compound from its reaction mixture until a later stage, and the present invention maybe carried out on the entire reaction ,mixture contalnlng the triethyltrltion.

ment with carbon disulphide and the oxidation with hydrogen peroxide are then carried out. The alkylated thiuramdisulphide and the mustard oil are removed as in the above examples, and the further treatment of the filtrate from the thiuramdisulphide' is also carried out as above. methylene triamine remains in the filtrate with the tertiaryv amine, from which itmay "be separated as follows:

' The filtrate containing the tertiary amine and the triethyltrimethylenetriamine is The triethyltri-- treated with an approximately equalfvolume Y of solution of sodium hydroxide or other suitable base. The tertiary amine is evolved and may be collected" in water orin' any suitable way. The polymerized'triethyltrimethylenetriamine may then be floatedofias an oil and collected. 1 p t i It is not essential *to the invention to ad just exactly the amount of tertiary amine' in the. mixture'ofaminesin any of'the above examples. "lVhere insufli cient tertiary amine is present to neutralize thev dithiocarb'amic acids, the filtrate from the thiuramdisulphide will contain primaryandsecondary amines together w th'tertiary amine and must be separated therefrom or otherw se util zed.-

An'excessl oftertiary amine, will impart an' alkaline reaction to the mixture after the treatment" with carbon disulphide.- If the tertiary amine be of a volatile nature, care must be taken to prevent the loss of the amine, either by collecting its Vapors or by proceeding under conditions adapted to prevent its volatilization. Y

I An excess of non-volatiletertiary amine may interfere physically or chemically with the most satisfactory progress ofthe reach W Vhere only primary and secondary amines are originally present, any other suitable base maybe added, provided"the base chosen does notreact with the carbon disulphide'orotherwise interfere with the progress-of the reaction, and will form a sufficiently stable salt with the dithiocarbamic acid, and does reaction.

Having thus described our invention,--what we claim rent is and desire to protect by LettersPatvprocess for treating I a mixture of amines which comprises reacting with carbon'bisulphide on the primary and secondary amines therein, oxidizingthe reaction products in the presence of an acid to therenotinterfere in any way with theoxidation by form an insoluble material, removing the insoluble material from the solution, and recovering. tertiary amine fromthe'solution'.

'2. A process for treating a mixture of amines whlch comprises react1ng-w1thcair- ,bon bisulphide on the primary and second-' ary'amines' therein and oxidizing the rea'c-j tio'n products in the presence of a mineral acid, separating the insoluble oxidation products from the solution, and recovering free tertiary amine from the filtrate/by treatment with a base. r

3. A. process for treating a mixture of amines which comprises'reacting on the primary and secondary amines therein with carbon bisulphide, oxidizing the reaction products with hydrogen peroxide inthe presence of sulphuric acid to form alkylated thiuram disulphide and mustard oil, removing the oxidized reaction products, separating out the alkylated thiuramdisulphide from the mus tard oil formed, treating the residues with a base,'and distilling and recovering'free ter tiary amine therefrom. I

' 4. A process fortreating a. mixture of amines which comprises reacting on primary and secondary amineswith carbon bisulphide, oxidizing the reaction pro-ducts with h drogen peroxide in the presence of sulg uric acid to form alkylated thiuram isulphide' and mustard oil, removing the oxidizedcproducts, separating out the alkylated thiuramdisulphide from the mustard oil formed, treating the residues with a base, distilling and recovering freetertiary amine therefrom, and repeating the treatment of residual amines with carbon bisulphide, oxidationv and separation until the filtrate contains tertiary amine only, and recovering the tertiary amine therefrom.

5. A process :for treating a mixture of amine salts which comprises liberating the free amines in solution, reacting with carbon bisulphide onthe primary and secondary amines therein, oxidizing the reaction products to an insoluble state by means of a per oxide in the presence of a mineral acid, re-- moving the insolublematerial from the solue tion, and recovering tertiary amine from the solution.

6. A process for treating a mixture of amine salts which comprises liberating the free amines in solution by treatment with sodium hydroxide, reacting with carbon bisulphide on the primary and secondary amines therein and oxidizing the reaction products in the presence of an acid adapted to form a soluble salt with the liberated primary,secondary and tertiary amines, remov-.

dues by treatment with a base.

8. A process for treating a mixture of amine salts which comprises liberating the free amines in solution by treatment with sodium hydroxide, reacting on theprimary and secondary amines with carbon bisulphide, oxidizing the reaction products with hydrogenvperoxide in theupresence of sulphuric acid to form alkylated thiuram disulphide and mustard oil removing the oxidized reaction products from the mixture, separating out the alkylated thiuramdisulphide from the mustard oil formed, treating the residues with a base, and distilling and recovering fre'e tertiary amine therefrom.

9, A process for treating a mixture of amine salts which comprises liberating the free amines in solution by treatment with sodium hydroxide, reacting on the primary and secondary amines with carbon bisulphide, oxidizing the reaction products with hydrogen peroxide in the presence of sulphuric acid to form alkylated thiuram disulphide and'must'ard oil, removing the insoluble oxidized 'products from the mixture, separating out the alkylated thiuramdisulphide from the mustard oil formed, treating the filtrate with a base, distilling and recovering free tertiary amine therefrom, and repeating the treatment with carbon bisulphide, oxidation and separation until the filtratecontains tertiary amine only.

10.'A process which comprises converting secondary amine into dithiocarbamate by treatment with carbon disulphide, making a thiuramdisulphide therefrom by oxidation in the presence of acid until substantially all of the secondary amine has been con-- verted into a thiuramdisulphide, and recovering the tetra alkylated thiuramdisulphide.

11. A process which comprises converting secondary amine in a mixture of amines into dithiocarbamate by treatment with carbon disulphide, making a thiuramdisulphide therefrom by oxidation in the presence of acid, and repeating said steps until substantially all of the secondary amine has been converted into ,a thiuramdisulphide, and recovering the tetra alkylated thiuramdisulphide'.

' 12. A process which comprises reacting on a secondary amine with carbon disulphide to forma dithiocarbamate, converting said .dithiocarbamate into a thiuramdisulphide by oxidation with a peroxide in the presence of a protective agent for the secondary amine liberated, recovering the thiuramdisulphide, recovering said secondary amine and retreating it to form a thiuramdisulphide therefrom, and recovering the'thiuramdisulphide.

13. A process which comprises treating a secondary amine with carbon disulphide, oxidizing the dithiocarbamate thus formed to a thiuramdisulphide with an inorganic oxidizing agent in the presence of an agent adapted to neutralize the amine liberated,

and recovering the thiuramdisulphide therefrom.

14. A process which comprises treating a secondary amine with carbon disulphide,

oxidizing the dithiocarbamate thus formed to a thiuramdisulphide with hydrogen peroxide in the presence of an agent adapted to neutralize the amine liberated, and recovering the thiuramdisulphide therefrom.

15. A- process which comprisestreating a secondary amine with carbon disulphide, oxidizing the dithiocarbamate thus formed to a thiuramdisulphide with hydrogen peroxide in the presence of a protective agent for the amine liberated, and recovering the thiuramdisulphide therefrom. I

16. A process which comprises treating a secondary amine with carbon disulphide,

oxidizing the dithiocarbamat-e thus formed to a thiuramdisulphide with hydrogen peroxide in the presence of inorganic acid, and recovering the thiuramdisulphidetherefrom.

17. A process which comprises treating a secondary amine with carbon disulphide,"

oxidizing the dithiocarbamate thus formed to a thiuramdisulphide with hydrogen peroxide inthe presence of sulphuric acid,'and

recovering the'thiuramdisulphide therefrom.

18. A process which comprises treating a secondary alkyl amine With carbon disulphide, oxidizing the alkyl dithiocarbamate thus formed to an alkylated thiuramdisulphide with hydrogen peroxide in the presence of sulphuric acid, and recovering the alkylated thiuramdisulphide therefrom.

19. A process which comprises treating dimethylamine with carbon disulphide, oxi- Signed at New-York, county and State of New York, this 31st day of July, 1925.

-HAR OLD s. ADAMS. Signed at Naugatuck, county of New Haven, State of Connecticut, this 30th dayof July, 1925.

LUDWIG MEUSER.

with' hydrogen CERTIFICATE OF CORRECTION. Patent No. 1,782,112. November 18, 1930.

He nry Van Arsdale, (Seal) Acting Commissionerof Patents. 

